According to a report in London, the United States will install the first leg of a civil administration to run post-war Iraq by Tuesday.

This constitutes a rebuff to Europe, which wants to stall the process until a role for the United Nations is agreed upon, The Observer said on Sunday.

The decision to proceed with an 'embryonic government' is in response to memoranda written by Defence Secretary Donald Rumsfeld last week, urging that the US should entrench its authority in areas under its control before the war is over.

Pentagon officials described the UN as 'irrelevant' and said that the administration is determined to impose the Rumsfeld plan.

Elements of a new administration will be established in the southern port of Umm Qasr, which is under the control of coalition forces, according to US officials in Doha.

The Pentagon's Office of Reconstruction and Humanitarian Assistance, under former US army lieutenant general Jay Garner, will install the administration.

"What we are going to start trying to do, even before the fighting is over in Iraq, is to move to the areas in Iraq that are relatively peaceful like Umm Qasr, and to start moving [the office of reconstruction] into Iraq," the officials said.